[Buildroot] [PATCH 3/4] swupdate: improved help text for Lua support

["Jörg Krause" <joerg.krause@embedded.rocks>]

On Mo, 2016-07-25 at 09:36 -0700, Jordan Yelloz wrote:

On 07/25/2016 12:32 AM, Thomas Petazzoni wrote:


Hello,

On Sun, 24 Jul 2016 16:27:38 -0700, Jordan Yelloz wrote:



-	??* Select BR2_PACKAGE_LUA if you want to have Lua
support.
+	??* Select BR2_PACKAGE_LUA or BR2_PACKAGE_LUAJIT if you
want to have Lua
+	????support.
+	????CONFIG_HANDLER_IN_LUA is not supported in LuaJIT or
Lua 5.1.
+	????swupdate must be manually configured with
CONFIG_LUAVERSION="jit-5.1"
+	????to link against luajit.


What does this last sentence means?

Thomas



Regarding CONFIG_LUAVERSION, this is trying to explain how to
successfully configure swupdate to build against LuaJIT. If you just
choose LuaJIT, it will not be successful automatically due to some
minor
limitations in the swupdate build system.

swupdate has some build rules that are not that good (it uses
pkg-config for some parts of the build but uses a secondary list of
library names to actually link the final executable against) and when
adding the Lua library to the list of libraries to link, it relies on
concatenating "lua" with $(CONFIG_LUAVERSION).

Basically, the only way to get swupdate to link against libluajit-
5.1.so
is to ensure CONFIG_LUAVERSION="jit-5.1" is in your swupdate KConfig
file. To me, the easiest/safest way of handling that is to expect the
user to configure swupdate manually with that value.


I like the idea of using swupdate with LuaJIT!

How about setting LUAVERSION if LuaJIT is selected? Like adding this somewhere:

$(call KCONFIG_SET_OPT,CONFIG_LUAVERSION,"jit-5.1")

Best regards
J?rg Krause